1,722 research outputs found

    The Impact of Trade Costs on Firm Entry, Exporting, and Survival in Korea

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    This study uses a unique firm-level dataset to examine how falling trade costs from 1993-2001 affected entry, exit, productivity, and exporting in the Korean manufacturing sector. We verify many of the predictions of recent heterogeneous-firm models of international trade. For example, falling trade costs reduced entry by new Korean firms, increased their probability of exit, and reduced the market share of surviving firms. We also find that small firms had a particularly high level of dynamism over the sample period. Small firms were more likely to enter and exit, and marginally more likely to gain market share, enter export markets for the first time, and improve their productivity.Employment, Exit, Exports, Firm deaths, Survival, Trade costs, Agribusiness, Industrial Organization, International Development, International Relations/Trade, Labor and Human Capital, Marketing, Production Economics, Productivity Analysis, Research and Development/Tech Change/Emerging Technologies, F10, D24,

    Non-adiabatic effects in periodically driven-dissipative open quantum systems

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    We present a general method to calculate the quasi-stationary state of a driven-dissipative system coupled to a transmission line (and more generally, to a reservoir) under periodic modulation of its parameters. Using Floquet's theorem, we formulate the differential equation for the system's density operator which has to be solved for a single period of modulation. On this basis we also provide systematic expansions in both the adiabatic and high-frequency regime. Applying our method to three different systems -- two- and three-level models as well as the driven nonlinear cavity -- we propose periodic modulation protocols of parameters leading to a temporary suppression of effective dissipation rates, and study the arising non-adiabatic features in the response of these systems.Comment: 12 pages, 8 figure

    Mars Micromissions

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    A Mars micromission launches as an Ariane 5 secondary as early as November I, 2002. One possible mission is a Comm/nav micromission .orbiter. The other possible mission is a Mars airplane. Both missions are enabled by a lowcost, common micromisson bus design. The future of Mars micromissions has at least two micromissions per Mars Opportunity In cooperation with CNES. Other destinations besides Mars are possible by small changes and technology Infusion in the micromission system design detailed here. Micromissions enable a new class of science investigations and comm/nav orbiters due to low-cost, focused design

    Tuning the exciton g-factor in single InAs/InP quantum dots

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    Photoluminescence data from single, self-assembled InAs/InP quantum dots in magnetic fields up to 7 T are presented. Exciton g-factors are obtained for dots of varying height, corresponding to ground state emission energies ranging from 780 meV to 1100 meV. A monotonic increase of the g-factor from -2 to +1.2 is observed as the dot height decreases. The trend is well reproduced by sp3 tight binding calculations, which show that the hole g-factor is sensitive to confinement effects through orbital angular momentum mixing between the light-hole and heavy-hole valence bands. We demonstrate tunability of the exciton g-factor by manipulating the quantum dot dimensions using pyramidal InP nanotemplates

    Cooperative Carbon Dioxide Adsorption in Alcoholamine- and Alkoxyalkylamine-Functionalized Metal-Organic Frameworks.

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    A series of structurally diverse alcoholamine- and alkoxyalkylamine-functionalized variants of the metal-organic framework Mg2 (dobpdc) are shown to adsorb CO2 selectively via cooperative chain-forming mechanisms. Solid-state NMR spectra and optimized structures obtained from van der Waals-corrected density functional theory calculations indicate that the adsorption profiles can be attributed to the formation of carbamic acid or ammonium carbamate chains that are stabilized by hydrogen bonding interactions within the framework pores. These findings significantly expand the scope of chemical functionalities that can be utilized to design cooperative CO2 adsorbents, providing further means of optimizing these powerful materials for energy-efficient CO2 separations

    Incidence and prevalence trends of youth-onset type 2 diabetes in a cohort of Canadian youth: 2002-2013.

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    OBJECTIVE: Youth-onset type 2 diabetes is an emerging disease. We estimated incidence and prevalence trends of youth-onset type 2 diabetes between 2002 and 2013 in the Canadian province of British Columbia. METHODS: This population-based cohort study used a validated diabetes case-finding definition and algorithm to differentiate type 2 from type 1 diabetes to identify youth <20 years with type 2 diabetes within linked population-based administrative data. Age-standardized incidence and prevalence were calculated. JoinPoint regression and double exponential smooth modeling were used. RESULTS: From 2002/2003 to 2012/2013, the incidence of youth-onset type 2 diabetes increased from 3.45 (95% confidence interval, CI: 2.43, 4.80) to 5.16 (95% CI: 3.86, 6.78)/100 000. The annual percent change (APC) in incidence was 3.74 (95% CI: 1.61, 5.92; P = 0.003) overall, while it was 5.94 (95% CI: 1.84, 10.20; P = 0.009) and 0.53 (95% CI: -5.04, 6.43; P = 0.837) in females and males, respectively. The prevalence increased from 0.009% (95% CI: 0.007, 0.011) in 2002/2003 to 0.021% (95% CI: 0.018, 0.024) in 2012/2013 with an APC of 7.89 (95% CI: 6.41, 9.40; P < 0.0001). In females, it increased from 0.012% (95% CI: 0.009, 0.015) to 0.027% (95% CI: 0.023, 0.032) and in males from 0.007% (95% CI: 0.005, 0.009) to 0.015% (95% CI: 0.012, 0.019). By 2030, we forecast a prevalence of 0.046% (95% CI: 0.043, 0.048). CONCLUSIONS: Youth-onset type 2 diabetes is increasing with higher rates in females vs males. If these rates continue, in 2030, the number of cases will increase by 5-fold. These data are needed to set priorities for diabetes prevention in youth

    Gadobenate Dimeglumine as an Intrabiliary Contrast Agent: Comparison with Mangafodipir Trisodium with Respect to Non-dilated Biliary Tree Depiction

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    OBJECTIVE: To compare the efficacy of Mangafodipir trisodium (Mn-DPDP)-enhanced MR cholangiogrphy (MRC) and Gadobenate dimeglumine (Gd-BOPTA)-enhanced MRC in visualizing a non-dilated biliary system. MATERIALS AND METHODS: Eighty-eight healthy liver donor candidates underwent contrast-enhanced T1-weighted MRC. Mn-DPDP and Gd-BOPTA was used in 36 and 52 patients, respectively. Two radiologists reviewed the MR images and rated the visualization of the common duct, the right and left hepatic ducts, and the second-order branches using a 4-point scale. The contrast-to-noise ratio (CNR) of the common duct to the liver in the two groups was also compared. RESULTS: Mn-DPDP MRC and Gd-BOPTA MRC both showed similar visualization grades in the common duct (p=.380, Mann-Whitney U test). In the case of the proximal bile ducts, the median visualization grade was significantly higher with Gd-BOPTA MRC than with Mn-DPDP MRC (right hepatic duct: p=0.016, left hepatic duct: p=0.014, right secondary order branches: p=0.006, left secondary order branches, p=0.003). The common duct-to-liver CNR of the Gd-BOPTA MRC group was significantly higher (38.90+/-24.50) than that of the Mn-DPDP MRC group (24.14+/-17.98) (p=.003, Student's t test). CONCLUSION: Gd-BOPTA, as a biliary contrast agent, is a potential substitute for Mn-DPDP.ope
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